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Biomedical subjects

M A Jacobs

Publications and source records attributed to M A Jacobs.

At least 19 recordsLinked to original sources
PubMed1992

Quantitative effects of cerebral infarction on spatial learning in rats.

Outcome following stroke is difficult to measure because the behavioral response to infarction is variable. We hypothesized that cognitive function, such as spatial learning, may be a reproducible and sensitive outcome variable. We developed an animal model of multifocal cerebral ischemia in order to study the effects of infarction on learning. To cause ischemia, several hundred microspheres were injected into the internal carotid arteries of rats. After ischemia, behavior was measured using a global rating and a Morris water maze. Postmortem serial brain sections were stained and the size of the infarctions was measured. We found that intracerebral microspheres caused cortical infarction and an impairment of spatial learning. This impairment was not due to occlusion of the internal carotid artery and was not found in animals who received a sham injection of saline. The degree of learning impairment was not correlated with the volume density of the infarctions or with the volume density of the remaining cerebral hemisphere. The learning impairment clearly differentiated normal from lesioned animals, and the impairment was probably due to a delay in acquisition of spatial information rather than a defect in retention or retrieval. Measurement of learning deficit after cerebral ischemia is an efficient and sensitive method for evaluating new stroke treatments and possibly for exploring structure function relationships.

Animals↗
PubMed1989

Bladder leiomyoma.

We herein present a case of leiomyoma of the urinary bladder discovered during evaluation for stress urinary incontinence. The histologic findings of this benign tumor and its urologic implications are reviewed.

Adult↗
PubMed1989

Intertrochanteric osteotomy for avascular necrosis of the femoral head.

Of 24 intertrochanteric osteotomies for avascular necrosis of the femoral head, 22 were followed up for an average of 63 months. Sixteen of the 22 cases had good or excellent results, including 5 of the 6 cases with Stage II disease and 11 of the 16 with Stage III changes. Success seemed to be inversely related to the size of the lesion. There were six major orthopaedic complications, but despite these we feel that the operation has a definite role in the treatment of the young active patient.

Adult↗
PubMed1989

Core decompression of the distal femur for avascular necrosis of the knee.

From 1974 to 1981, we performed 28 core decompressions of the distal femur for pathologically confirmed avascular necrosis. At a mean follow-up of 54 months (range 20 to 140 months) and using the Ficat stages, all seven cases in stage I and stage II had good results. Of 21 cases in stage III, 11 cases had good results, four had poor results, and six needed total knee replacement. There were no significant orthopaedic complications. The procedure is worthwhile and will be more accurate with new methods of imaging.

Adult↗
PubMed1989

Osteotomy of the tibial tubercle during total knee replacement. A report of twenty-six cases.

The cases of twenty-four patients who had twenty-six osteotomies of the tibial tubercle in conjunction with total knee replacement were analyzed with regard to complications and technical considerations. The patients were followed for a minimum of two years (average, three years and six months). Major complications related to the surgical technique occurred in 23 per cent of the knees and complications not related to the technique, in an additional 8 per cent. Rheumatoid arthritis and a history of at least one previous operation about the knee were predisposing factors for these complications.

Adult↗
PubMed1989

Revision of septic total knee arthroplasty.

Nine patients with septic total knee arthroplasties (TKA) were treated between 1980 and 1984; six were gram-positive infections and three were gram-negative. Initial treatment included the maintenance of all solidly fixed components. Patients with loose components were treated with removal of all prosthetic material and subsequent reimplantation after a six-week course of antibiotics. At follow-up examination six of nine patients had satisfactory results. One patient maintained his original femoral and tibial components and one patient required a knee fusion to treat his recurrent gram-negative infection. Overall, complications were associated with chronic infection, gram-negative infection, and abnormalities of the extensor mechanism.

Arthritis, Infectious↗
PubMed1988

Revision total knee arthroplasty for aseptic failure.

Twenty-four patients with 28 failed total knee arthroplasties replaced with porous-coated anatomic (PCA) primary or revision components were studied over a two- to four-year period. Overall, there were 68% good and excellent results and three failures. When evaluated according to mode of failure, 83% of the patients who had a definable mechanical problem achieved good or excellent results. Patients who had revision operations for incapacitating pain or in whom no clearly definable problem could be ascertained before operation were not significantly improved. Complications that led to poor results were deep sepsis, wound necrosis, and extensor mechanism abnormalities.

Aged↗
PubMed1985

The effects of a dietary zinc supplement during lactation on longitudinal changes in maternal zinc status and milk zinc concentrations.

Dietary zinc intakes, selected biochemical indices of zinc status, and milk zinc concentrations were determined at monthly intervals throughout lactation for 53 middle-income lactating women, 14 of whom received a daily supplement of 15 mg zinc. Overall mean dietary zinc intake for the non-supplemented group (NZS) was 10.7 +/- 4.1 mg/day (mean +/- SD). The mean dietary zinc intake of the zinc supplemented group (ZS) was 12.2 +/- 3.5 mg/day, with an additional 12.8 +/- 1.5 mg/day from the supplement. For the NZS group, the highest mean plasma zinc concentration of 79 +/- 10 mu/dl, which occurred at month 4, was significantly less than the mean for non-lactating control women (86 +/- 10 micrograms/dl). ZS plasma zinc levels had a pattern similar to that of the NZS group for months 1-7. The rate of decline in milk zinc during lactation was significantly less for the ZS group compared to that of the NZS group (p = 0.02). It is concluded that milk zinc concentrations are influenced by maternal zinc intake within a physiological range and that the effects of low maternal intakes are most apparent with prolonged lactation.

Adult↗
PubMed1985

Zinc in human milk: diurnal and within-feed patterns.

To examine diurnal patterns of milk zinc concentrations, midfeed samples were obtained at approximately 6 a.m., 9 a.m., 12 noon, 3 p.m., 6 p.m., and 9 p.m. on a total of 29 days from 16 lactating women. Within-feed patterns were examined in 32 subjects with analysis of samples of fore-, mid-, and hindmilk from a total of 175 feeds. There were no significant differences between means for any of the diurnal intervals or between means for fore-, mid-, and hindmilk samples. These results indicate that milk zinc concentrations of random samples of human milk collected at any time of the day or of the feed can be accepted as representative for that day.

Breast Feeding↗
PubMed1984

Kinematic total knee replacement.

We reviewed 124 consecutive kinematic condylar total knee replacements (in ninety-one patients) at two to four years postoperatively. One hundred and eleven (90 per cent) were rated as good or excellent. The average active postoperative flexion was 106 degrees (range, 94 to 120 degrees). Twenty-two knees (18 per cent) had incomplete, non-progressive radiolucent lines, less than one millimeter in width, at the tibial bone-cement interface; these were considered insignificant. Restriction of stair-climbing ability in this series appeared to be a function of involvement of multiple joints rather than of patellar replacement, as the rheumatoid patients with resurfaced patellae performed the worst. The osteoarthritic patients with involvement of a single joint performed the best, regardless of whether the patella was resurfaced or not. When compared with a similar series of total knee replacements in which the tibial component was made entirely of plastic, less reaction at the bone-cement interface was found with the metal-backed kinematic tibial component. We suggest that this finding is clinical confirmation of in vitro studies that demonstrated the advantage of metal-backed tibial components. We concluded that this procedure, if meticulously performed, will give predictably good to excellent results with a low complication rate, a good postoperative range of motion, and a favorable-appearing bone-cement interface at two to four years.

Adult↗
PubMed1983

Zinc nutritional status during pregnancy: a longitudinal study.

Dietary zinc (Zn) intake and selected biochemical indices of Zn status were studied longitudinally at monthly intervals in 46 pregnant middle-income women, 10 of whom received a daily supplement of 15 mg Zn. Mean dietary Zn intake for the nonsupplemented subjects (group A) was 11.3 +/- 4.1 mg/day (56% of the Recommended Dietary Allowances), and for the Zn-supplemented subjects (group B) was 21.7 mg/day (109% of the Recommended Dietary Allowance), including an average intake of 11.1 mg/day as supplemental Zn. The mean plasma Zn concentration of group A at 2 months gestation, 71.4 +/- 9.8 micrograms/dl, was 17% lower than that of nonpregnant control women, and continued to decline significantly (p less than 0.01) between 2 and 10 months gestation. Plasma Zn of group B did not differ significantly from group A at any stage of gestation. Mean serum alkaline phosphatase activity of group B was higher than that of group A at 7 of 8 months studied (p less than 0.05). The level of prenatal iron supplementation in group A was negatively correlated with alkaline phosphatase activity and plasma Zn in the 2nd and 3rd trimesters, respectively. It is concluded that an early and progressive decline in plasma Zn which is not influenced by Zn intake occurs during gestation. Tentative standards for lower limits of normal at monthly intervals have been suggested. The higher alkaline phosphatase activity of group B compared with group A suggested that the dietary Zn intake of the latter was suboptimal. Prenatal supplemental iron may adversely affect maternal Zn status.

Adolescent↗
PubMed1981

Interaction of therapeutic attitudes with severity of clinical diagnosis.

Investigated whether therapeutic processes, measured by self-reported attitudes of therapists, are differential or generalized; i.e., whether particular types or all types of patients benefit from a given level of a professed technique. Three therapeutic variables (empathic warmth, directiveness, and uncovering), identified by factor analysis, were studied in interaction with two levels of clinical pathology. A total of 161 patients were seen in psychodynamically oriented individual psychotherapy by 22 therapists. Independent ratings of global improvement were made. Results indicated that high scores on empathic warmth and uncovering appear to be more helpful for patients with neurotic and personality trait disorder diagnoses than for patients with borderline and psychotic diagnoses. Low scores on directiveness seemed to be associated with effectiveness in a more general way (across diagnostic groups). For the most part, reference to therapeutic attitudes as helpful or harmful must take into account the particular diagnostic groups that are being treated.

Adolescent↗