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Biomedical subjects

D H Huber

Publications and source records attributed to D H Huber.

At least 19 recordsLinked to original sources

Transmissible mitochondrial hypovirulence in a natural population of Cryphonectria parasitica.

A cytoplasmically transmissible hypovirulence syndrome has been identified in virus-free strains of the chestnut blight fungus Cryphonectria parasitica isolated from healing cankers on American chestnut trees in southwestern Michigan. The syndrome is associated with symptoms of fungal senescence, including a progressive decline in the growth potential and abundance of conidia, and elevated levels of respiration through the cyanide-insensitive alternative oxidase pathway. Conidia from senescing mycelia exhibited varying degrees of senescence ranging from normal growth to death soon after germination. Cytoplasmic transmission of hypovirulence between mycelia occurred by hyphal contact and coincided with the transfer of a specific restriction fragment length polymorphism from the mitochondrial DNA (mtDNA) of the donor strains into the mtDNA of virulent recipients. The transmission of the senescence phenotype was observed not only among vegetatively compatible strains but also among incompatible strains. Hypovirulence was present in isolates from the same location with different nuclear genotypes as identified by DNA fingerprinting. This study confirms that mitochondrial hypovirulence can occur spontaneously and spread within a natural population of a phytopathogenic fungus.

Ascomycota↗

Postpartum IUDS: keys for success.

Intrauterine device (IUD) insertion is convenient and efficient in the postplacental and immediate postpartum periods. Insertion at these times is demonstrably safe, having a low incidence of infection, few bleeding problems, and low perforation rates. IUD expulsion rates can vary widely, and are a function of timing of insertion, type of IUD, and insertion technique. When a copper T device is inserted postplacentally or immediately postpartum by an experienced and trained clinician, expulsion rates of about 7-15 per 100 users at six months can be expected. Women must be told how to detect expulsions and instructed to return for reinsertion or for another method. Most investigators emphasize that high fundal IUD placement will reduce the expulsion rate. Unplanned pregnancy rates for postplacental IUD insertion range from 2.0-2.8 per 100 users at 24 months when using modern copper IUDs, correct insertion technique, careful postinsertion instructions and good follow-up. Postplacental insertions are performed manually or with a ring forceps. Immediate postpartum insertions (10 minutes to 48 hours after delivery) are performed with the ring forceps.

Contraception↗

Declining mortality in international sterilization services.

Between 1973 and 1988, AVSC supported 1,516,478 female sterilizations and 401,856 vasectomies in 50 countries. Overall, 73 deaths were attributable to voluntary sterilization procedures (yielding mortality rates of 4.7 deaths per 100,000 female sterilizations and 0.5 per 100,000 vasectomies). Causes of death, in order of frequency, were anesthesia (22), intestinal injury (20), infection (19), intra-abdominal hemorrhage (6) and other (6). The female sterilization mortality rate declined from 7.1 per 100,000 procedures in 1973-1981 to 3.7 per 100,000 in 1982-1988. Safer anesthesia practices and improved infection control contributed most to this decline. The mortality rate related to surgical errors declined proportionately less than the rates related to anesthesia and infection. Contraceptive sterilization has become a very safe procedure in these 50 countries, where anesthesia (local and general), surgical technique (minilaparotomy and laparoscopy) and timing of the procedure (interval and postpartum) vary substantially. Future deaths will probably be rare. However, expert surgeons should review each case because identifying the most likely cause of death is always complex and these analyses help shape surgical contraception practices.

Cause of Death↗

No-scalpel vasectomy at the King's birthday vasectomy festival.

No-scalpel vasectomy was developed to increase acceptability of vasectomy by elimination of the fear of the incision. Although this method has been used for over 8,000,000 men, the technique is largely unknown in developed countries. During the King's birthday vasectomy festival no-scalpel vasectomy was compared with standard incisional vasectomy in 1203 patients. An average of 57 procedures per day could be done by each physician with the no-scalpel method, compared to 33 procedures with the standard method (p less than 0.001). The complication rate was 0.4/100 procedures for no-scalpel vasectomy compared with 3.1/100 for standard vasectomy (p less than 0.001). No-scalpel vasectomy is a rapid and economic alternative to standard vasectomy, with fewer complications and increased patient acceptability.

Constriction↗

Vasectomy: an appraisal for the obstetrician-gynecologist.

Data regarding the efficacy of vasectomy are limited, but the procedure appears to be highly effective. Efficacy may vary by the method of vas occlusion. Death attributable to vasectomy in the United States is exceedingly rare, and major perioperative morbidity is quite uncommon. No long-term adverse health effects have been documented, and much evidence supports the conclusion that vasectomy does not increase the risk of subsequent atherosclerosis. Vasectomy, like tubal sterilization, should be considered a permanent decision, because reversal surgery is expensive and requires substantial surgical expertise. Although vasectomy reversal is often successful, it cannot be guaranteed even in the best of circumstances, and when the vasectomy has caused epididymal obstruction, reversal is often unsuccessful. Vasectomy represents a safe and effective alternative to tubal sterilization for couples who decide that the male should be sterilized.

Female↗

Complications of vasectomies in the United States.

Physicians in the United States were surveyed in 1983 to gather information concerning the number of vasectomies they performed in 1982 as well as their use of anesthesia and complications of those vasectomies. Most urologists performed vasectomies, whereas family physicians and general surgeons were less likely to do so. As expected, most physicians used local anesthesia, occasionally in combination with a sedative; however, 22 percent of physicians reported using general anesthesia for at least some vasectomies. Complication rates were in the ranges reported by previous case series. Physicians who performed between one and ten vasectomies in 1982 had higher rates of hematoma and hospitalization for treatment of a complication than physicians who performed more vasectomies. Maintenance of surgical skills appears to be important in preventing complications of this usually low-risk procedure.

Anesthesia, General↗

Open laparoscopy. Commentary.

Open laparoscopy has been receiving increased attention in the US and internationally. However, opinions differ on its appropriate role in laparoscopy services. In the US some surgeons remain comfortable using closed laparoscopy for all patients, including some who have had previous abdominal surgery. Some centers are using more open procedures, especially for training programs and for cases where open laparoscopy may be indicated, as described by Dr. Hasson in this "Bulletin." Others have converted to performing all laparoscopy by the open technique. The Planned Parenthood Federation of America encourages minilaparotomy and open laparoscopy for tubal occlusion n its facilities because of the greater inherent potential for patient safety with these approaches. AVS has not provided open laparoscopy equipment to international programs, although some projects have used an open technique. Neither the World Federation of Health Agencies for the Advancement of Voluntary Surgical Contraception nor the AVS Science Committee has addressed the role of open laparoscopy in international programs. This is due in part to insufficient worldwide experience in open laparoscopy. However, this does not preclude AVS from providing such equipment for open laparoscopy in the future. In the US approximately 300-500 Hasson cannulas have been commercially distributed annually for the past 4-5 years. About 2000 may be currently in use in the US. Therefore, among the 6915 hospitals registered with the American Hospital Association in 1982, a substantial proportion may now provide access to open laparoscopy equipment. Studies in the US are not yet available to fully assess the safety of open laparoscopy. However, general comparisons of complication rates for open and closed laparoscopy may not be appropriate since many surgeons reserve the more complicated cases for open laparoscopy.

Americas↗

Oral contraceptives and family health in rural Bangladesh.

A case-control survey of mothers was undertaken in rural Bangladesh to assess the health problems of oral contraceptive users compared with two groups of nonusers. The complaint most often reported was weakness--more than 80% of all women surveyed. Significantly more pill users than nonusers reported experiencing dizziness and eye problems. However, only one fifth of dizziness complaints among pill users could be attributed to the pill. Although more pill users reported a decrease in lactation, a greater problem among the control group was total cessation of lactation related to a subsequent pregnancy. Therefore, in this context the pill may postpone weaning more often than it reduces lactation. That few women choose to use oral contraceptives in the early postpartum period, when a reduction in breast milk would be most hazardous to the child, contributes to this favorable balance. The attitude toward early termination of pregnancy was positive for 61% of pill users and 34% of nonusers. It is likely that abortion services would be favorably received in this traditional society.

Abortion, Induced↗

Diarrhoeal disease in Bangladesh: epidemiology, mortality averted and costs at a rural treatment centre.

The basic epidemiology of acute diarrhoeal disease seen at a rural Bangladesh hospital in 1975 is reviewed. V. cholerae 01 was isolated from 28% of 1 964 patients. Significant differences in hospitalisation rates were observed between males and females in several age groups. Overall hospital case fatality was 9/1000 cases. We estimate that approximately a quarter to half of the hospitalised patients would have died had no rehydration therapy been available. The region's total mortality was reduced by approximately 7%-15%, at a cost of United States $0.14 per capita. Mortality from acute diarrhoeal diseases was greatly reduced for all age groups, and total mortality and mortality from all diarrhoeal diseases were particularly reduced for young children and young adults. Rehydration therapy used in a field hospital was apparently highly effective in reducing general mortality and mortality from acute diarrhoeal diseases.

Adolescent↗

Reduction of neonatal tetanus by mass immunization of non-pregnant women: duration of protection provided by one or two doses of aluminium-adsorbed tetanus toxoid.

Immunization of non-pregnant women in rural Bangladesh with two doses of aluminium-adsorbed tetanus-diphtheria toxoids reduced neonatal mortality by one-third during a period of 9-32 months after vaccination. The reduction in mortality rate was attributable almost entirely to a 75% lower mortality rate among 4-14-day-old infants, when tetanus was the predominant cause of death.In the period up to 20 months following vaccination, the reduction in deaths among 4-14-day-old infants after a single dose of tetanus-diptheria toxoids was about the same as that after two doses. However, beyond 20 months a single dose did not appear to provide protection.

Adolescent↗

Screening oral contraceptive candidates and inconsequential pelvic examinations.

Among 1,201 women who requested oral contraceptives (OCs) at a large London family planning clinic between 1 January 1971 and 9 March 1971, 51 (5 percent) were initially denied this method because of contraindications discovered by medical histories and examinations. Twenty-four of the 51 women received OCs at subsequent visits, raising the overall proportion receiving OCs to 97.4 percent. Initial screening procedures detected 44 contraindications by medical history, six by blood pressure determination, one by breast examination, and none by pelvic examination. Examination by a physician did not appear to be essential in the screening process at this clinic.

Adult↗