Ukucwaninga Ngezilwane—Isibusiso Noma Isiqalekiso?
UMA uphakathi kwezigidi eziningi zabantu ezaphefumula okokuqala umoya wokuphila ngasekuqaleni kwalelikhulu leminyaka, kungenzeka wazi kahle ukuthi usudle anhlamvana ukwedlula kude lokho abazali bakho nodokotela noma umbelethisi abakuletha lapha abakulindele. Uma wazalelwa eUnited States, eCanada, noma eYurophu, isikhathi sokuphila kwakho esasilindelekile ngonyaka ka-1900 sasicishe sibe iminyaka engu-47. Kwamanye amazwe amandla okuphila ayengaphansi ngisho kwalokho. Namuhla, emazweni amaningi isilinganiso sokuphila esilindelekile singaphezu kweminyaka engu-70.
Kungakhathaliseki ukuthi umdala kangakanani, uphila esikhathini esiyindida. Abazali babazali bakho noma okhokho bakho babona imiphumela engalawuleki yezifo eziningi ezabulala ingxenye enkulu yesizukulwane sabo. Ngokwesibonelo, ingxibongo yathatha ukuphila kwezinkulungwane ezingenakubalwa unyaka nonyaka futhi yashiya izigidi zabanye zinezibazi ezingeke ziphele. Imfuluwenza yabulala inani layo—ubhadane olulodwa kuphela lwenezela ukufa kwezigidi ezingu-20 zabantu ngonyaka owodwa (1918-1919). Ngemva kweMpi YeZwe I, ubhadane lomkhuhlane onamandla obangelwa isifo sezintwala lwabulala izigidi ezintathu zabantu eRussia. Lolubhadane lomkhuhlane lwahlasela nakwamanye amazwe amaningi phakathi neMpi YeZwe II. Kulinganiselwa ukuthi abantu abangu-25 kwabangu-100 abangenwa yilomkhuhlane phakathi nalolubhadane bafa.
Isifo esesabekayo sokukhubazeka kwezinsana (infantile paralysis), kamuva esaziwa ngokuthi ipoliomyelitis, sanciphisa izakhamuzi zomhlaba ngabantu abangu-30-000 unyaka nonyaka futhi sakhubaza izinkulungwane zabanye, ikakhulukazi izingane. Kwakunalabo abasebancane ngeminyaka abangazange baphunyuke egalelweni lokuqala lomkhuhlane obangela ukusha kwamathumbu noma isifo esivimbanisayo sokusha komphimbo, iscarlet fever noma isimungumungwane, ukukhwehlela ngenxa yesifuba esicinene, noma isishiso samaphaphu. Loluhlu lubonakala lungapheli. Cishe abantwana abangu-10 000 kwabangu-100 000 abazalwa ngo-1915 bafa ngaphambi kokuba baqede unyaka wabo wokuqala. Amaqhubu asebuchosheni ayengahlinzeki. Ikhono lokuvula imithambo evalwe igazi elingamahlule lalingaziwa. Odokotela babengenawo amandla okusindisa izisulu zesifo senhliziyo, futhi umdlavuza wabangela ukufa kwabanye.
Naphezu kobhadane lwezifo ezibulalayo eziye zonakalisa izwe kusukela ekuqaliseni kwalelikhulu leminyaka nangaphambi kwalokho, iminyaka yokuphila komuntu elindelekile namuhla iye yanda ngeminyaka ecishe ibe ngu-25. Ngakho, ezingxenyeni eziningi zomhlaba, ingane ezalwe namuhla kulindeleke ukuba iphile iminyaka elinganiselwa ku-70.
Inani Elikhokhwayo Ukuze Kusindiswe Ukuphila
Ngenhlanhla, intsha eningi ephilayo namuhla iye yasinda ezifweni eziningi ezibulalayo ezaziyimbangela yokufa kokhokho bayo abaningi. Kodwa ingase ingakujabuleli ukwazi ukuthi abaningi babangane bomuntu abanoboya—izinja, amakati, onogwaja, izinkawu, nokunye—benziwa umhlatshelo ngenjongo yesayensi yezokwelapha ‘ukuze abantu namuhla baphile ukuphila okude nokunempilo,’ njengoba ososayensi bekuchaza kanjalo.
Cishe zonke izifo eziye zaqedwa noma zalawulwa kulelikhulu leminyaka—ipolio, isifo sokuvimbana komphimbo, uzagiga, isimungumungwane, irubella, ingxibongo, nezinye—ziye zanqotshwa ngenxa yokucwaninga ngezilwane. Izidambisi neziqedabuhlungu ezingalalisi, ukufakwa kokudla nemithi yokwelapha ngemithambo yegazi, ukwelashwa komdlavuza ngemisebe yamaelectron nangokusebenzisa amakhemikhali, konke kwahlolwa futhi kwabonakala kuphumelela okokuqala ezilwaneni. Futhi lokhu kumane nje kungokumbalwa kwakho.
“Cishe ayikho ngokuphelele indlela yokwelapha eyinhloko noma inqubo yokuhlinza kwezokwelapha zanamuhla ebingavezwa ngaphandle kokucwaninga ngezilwane,” kwasho isazi esiqavile sokusebenza kwesimiso semizwa, uDkt. Robert J. White. “Umsebenzi owenziwa ngezinja nangezinye izilwane waholela ekusungulweni kweinsulin nokulawulwa kwediabetes, ukuhlinzwa ngokuqaqwa kwenhliziyo, ukulinganiswa kwesigqi sokushaya kwenhliziyo kanye nokufakwa kwesicubu esiphelele. IPolio . . . cishe iye yasuswa ngokuphelele eUnited States ngemijovo yokugoma eyaqinisekiswa ezinkawini. Ngokusebenza ngezilwane, abacwaningi baye baveza isilinganiso sekhambi lezingane ezihlushwa iacute lymphocytic leukemia kusukela kumaphesenti amane ngo-1965 kuya kumaphesenti angu-70 namuhla,” kusho yena lodokotela.
Indima efezwa ukucwaninga ngezilwane iqinisekiswa owayewumsizi endaweni yokucwaninga uHarold Pierson, owasebenza ngaphansi kukaDkt. F. C. Robbins eYunivesithi yaseWestern Reserve, eseCleveland, eOhio, U.S.A. Watshela iPhaphama! ukuthi isimiso sabo sokuthola umuthi ophuzwayo wokugomela ipolio sasihilela ukusetshenziswa kwezinso zezinkawu. Isicubu esasithathwe ensweni eyodwa sasingasetshenziselwa ukuhlola okuyizinkulungwane. Wachaza: “Izinkawu zazigcinwa esimweni umuntu aphila kuso futhi ngaso sonke isikhathi zazifakwa izidambisi buhlungu lapho zihlinzwa. Ngokuqinisekile lwalungekho unya lwangamabomu. Nokho, ngenxa yesizathu sokuhlinzwa kwazo, zaziyizisulu zokuphoqwa zonya olungokwesayensi.”
Ukuhlinzwa Kwenhliziyo Ne“Alzheimer’s Disease”
Njengomphumela oqondile wokucwaninga ngezilwane, kuye kwathuthukiswa amakhono amasha ezokuhlinza imithambo yegazi evalwe inzika yecholesterol, ngaleyondlela kuvinjelwa izifo eziningi zenhliziyo—imbangela eyinhloko yokufa emazweni aseNtshonalanga. Ngokuhlola ngezilwane kuqala, odokotela bafunda indlela yokususa ngokuphumelelayo amaqhubu amakhulu ebuchosheni bomuntu futhi bavuselele izitho zesingenhla nesingezansi ezilimele kabi—izingalo, imilenze, izandla, neminwe. UDkt. Michael DeBakey, owenza ukuhlinza kokuqala okuphumelelayo kokuhamba kwegazi kuyicoronary artery, wathi: “Emsebenzini wami wokucwaninga ngezokwelapha, cishe yonke intuthuko yokuqala yeqembu elasiza ekucwaningeni okuphathelene nokuhlinzwa kwenhliziyo yayisekelwe ekucwaningeni ngezilwane.”
Ngokuphathelene neAlzheimer’s disease, uDkt. Zaven Khachaturian weU.S. National Institute of Aging wathi: “Eminyakeni eyisishiyagalombili edlule, sasingazi lutho. Kuye kwaba khona intuthuko emangalisayo ekucwaningeni ngeAlzheimer ngenxa yokulondoloza ulwazi lwethu ngokucwaninga okuyinhloko okuphathelene nokusebenza kwengqondo okuhlehlela emuva ko-1930.” Umsebenzi omkhulu wawuhilela izilwane, futhi udokotela waphawula ukuthi ziyisihluthulelo sentuthuko eqhubekayo.
Ingculaza ne“Parkinson’s Disease”
Ukucwaninga okubucayi kakhulu manje, nalokho okubangela ososayensi nezazi zokugoma ukuba basebenze isikhathi esengeziwe, okokuthola ikhambi lokunqoba isifo esesabekayo ingculaza, ezinye izazi ezilinganisela ukuthi iyobulala abantu abalinganiselwa ku-200 000 ngo-1991 eUnited States iyodwa. Ngo-1985 izazi zesayensi eNew England Regional Primate Center zaphumelela ekutholeni igciwane leSTLV-3 (SAIDS, uhlobo lwengculaza yezinkawu) ezinkawini ezingamamacaque nasekuyifakeni kwezinye. UDkt. Norman Letvin, isazi sezokugoma eNew England Regional Primate Center wathi: “Manje njengoba leligciwane selitholakele, sinesibonelo sesilwane lapho singaveza khona ikhambi lezinkawu nelabantu. Kungenzeka ukufunda okuningi kakhulu enanini elincane kakhulu lezilwane ekuhloleni okulawulwayo kunasekubukeleni amakhulu eziguli zabantu abaphethwe ingculaza.”
Odokotela baseYerkes Regional Primate Research Center yaseYunivesithi yase-Emory, eAtlanta babengabokuqala ukubonisa, ngokuhlola kwabo ngezinkawu ezingamarhesus, ukuba nokwenzeka kokufakela isicubu esikhiqiza idopamine engqondweni njengekhambi lesifo seParkinson. Kusukela ngo-1985 izazi zokuhlinza imithambo yemizwa bezihlinza abantu esiBhedlela saseYunivesithi yase-Emory. Odokotela banomuzwa wokuthi lokhu kungase kuholele ekuphumeleleni ukuthola ikhambi lalesifo.
Umuntu uye waphendukela ezilwaneni ekufuneni kwakhe izimpendulo emibuzweni ephicayo ngendlela yokuthuthukisa nokusekela, ngisho okwesikhashana, ukuphila kwakhe okungaphelele. Nokho, ukusetshenziswa kwezilwane ekucwaningeni ngemithi kuphakamisa izimpikiswano eziphawulekayo ezingokokuziphatha okungelula ukuzixazulula.
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Ukucwaninga Ngezilwane Umkhuba Wasendulo
UKUSETSHENZISWA kwezilwane okwenziwa odokotela nezazi zesayensi ukuze baqonde ukusebenza komzimba wabantu okusakazeke yonke indawo akuyona into engaziwa kulelikhulu lama-20 leminyaka. Izilwane ziye zasetshenziswa ekucwaningeni kwezokwelapha okungenani iminyaka engu-2 000. Ekhulwini lesithathu leminyaka B.C.E., eAlexandria, eGibithe, imibhalo egciniwe ibonisa ukuthi isazi sefilosofi nesayensi uErasistratus sasebenzisa izilwane ukuze sihlole imisebenzi eyenziwa umzimba futhi sayithola isebenza kubantu. Ekhulwini lesine leminyaka, isazi sesayensi esaziwayo esingumGreki, uAristotle ekuhloleni kwakhe ngezilwane wahlanganisa ukwaziswa okuwusizo ngokuphathelene nokwakheka kanye nokusebenza komzimba womuntu. Amakhulu amahlanu eminyaka kamuva isazi sokwelapha esingumGreki uGalen sasebenzisa izinkawu nezingulube ukuze siqinisekise imfundiso yaso yokuthi imithambo ithwala igazi kunokuthwala umoya.