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Biomedical subjects

L Howard

Publications and source records attributed to L Howard.

At least 91 records · Page 5Linked to original sources
PubMed1993

The ABC carbon and polyester prosthetic ligament for ACL-deficient knees. Early results in 31 cases.

We treated 39 knees with chronic deficiency of the anterior cruciate ligament by reconstruction using the ABC carbon and polyester prosthetic ligament; 31 (79.5%) were reviewed at an average follow-up of 34 months. There had been four complete failures requiring revision. The remaining 27 were studied in detail. On the Lysholm rating, only 11 knees (41%) had good results with a score of over 76. The mean anterior drawer movement was reduced from 7.6 mm before operation to 5.8 mm at review. The mean difference from the opposite uninjured knee was 3.9 mm before operation, 1 mm (in 21 patients) at mean follow-up of 7.4 months and 2.5 mm (in 27 patients) at 34 months, indicating progressive loss of effect. In our opinion the results are unsatisfactory: we do not recommend the use of this prosthetic ligament.

Adult↗
PubMed1993

Peritoneal dialysis therapy for patients with liver and renal failure with ascites.

Two patients with severe liver disease complicated with ascites were recently treated at our institution. Both rapidly developed renal failure. In one patient, liver disease was the result of alcohol abuse, and in the other, was due to malnutrition associated with obesity and acute weight loss. The only reasonable therapeutic approach for these patients was believed to be a course of peritoneal dialysis, along with other supportive measures. In both cases, the management was successful. Furthermore, it was possible to discontinue dialysis at the time of discharge. We conclude that peritoneal dialysis can be a life-saving procedure in patients with severe liver disease and ascites complicated by renal failure.

Ascites↗
PubMed1992

Hereditary flat adenoma syndrome: a variant of familial adenomatous polyposis?

We describe the clinical and pathologic features in four extended kindreds that are consistent with the hereditary flat adenoma syndrome (HFAS). This colon cancer susceptibility disorder is believed to be inherited as an autosomal dominant. The principal phenotypic marker is multiple colonic adenomas (usually less than 100), with a tendency for proximal location. The majority of these adenomas are flat or slightly raised and plaquelike, as opposed to polypoid. Colon cancers have typically developed in middle age and show no unusual histologic features. There are a variety of extracolonic manifestations, including adenomas and carcinomas of the small bowel and fundic gland polyps. The HFAS is contrasted with hereditary nonpolyposis colorectal cancer and familial adenomatous polyposis (FAP) and shown to be distinct from both in the numbers and distribution of colonic adenomas and the typical age of cancer diagnosis. The clinical implications of these findings are discussed. Given its linkage to the FAP locus on 5q and the phenotypic parallels between HFAS and FAP, we conclude that HFAS is a variant of FAP.

Adenoma↗
PubMed1992

Possible non-functional crypts in small intestine defined using mouse aggregation chimaeras.

We have identified a minor population of crypts in small intestine which do not appear to export cells to villi. These crypts can be observed in whole-mounts of small intestine prepared from C57BL/6J<-->SWR mouse aggregation chimaeras stained with a peroxidase conjugate of the lectin Dolichos biflorus agglutinin (DBA-Px). In preparations where by chance the C57BL/6J epithelium (positive staining) forms only a minor component of the chimaera, occasional crypts occur which are isolated from larger patches of C57BL/6J epithelium and are surrounded by SWR (non-staining) epithelium. Fifty-one of 383 isolated C57BL/6J crypts (13%) did not appear to export cells to villi, although the crypt mouth is surrounded by a small patch of C57BL/6J epithelium on the intervillus gut floor.

Animals↗
PubMed1992

Linkage of a variant or attenuated form of adenomatous polyposis coli to the adenomatous polyposis coli (APC) locus.

Adenomatous polyps are an intermediate in the pathway to colon carcinoma. An inherited disorder, familial adenomatous polyposis coli (APC), is characterized by hundreds to thousands of adenomatous polyps. A previously reported family had colon cancer associated with a low average but highly heterogenous number of colonic polyps, this phenotype mapped to the APC locus on 5q. Four new families have been ascertained in which the phenotypic pattern was different from classical polyposis but similar to that of the "prototype" kindred reported earlier. By multilocus linkage analysis, the gene responsible for the disease phenotype was mapped, with a high level of confidence, to the APC locus in two of the four families with the attenuated or variant form of polyposis (AAPC); the results for the two remaining kindreds were inconclusive. A combined maximum LOD score of approximately 7.6 at a recombination fraction of 0 was obtained when the results were summed over the four pedigrees with markers closest to the APC locus. The establishment of genetic linkage in such families may point to the APC locus as having a more significant role in inherited predispositions to colorectal cancer than was previously thought.

Adenomatous Polyposis Coli↗
PubMed1990

Confirmatory assay increases specificity of the chlamydiazyme test for Chlamydia trachomatis infection of the cervix.

Enzyme immunoassays for the detection of chlamydial antigens are commonly used to diagnose Chlamydia trachomatis infection. As is true for all nonculture methods, the specificities of these tests are a concern. A confirmatory blocking assay (Abbott Laboratories, North Chicago, Ill.) was evaluated at four sexually transmitted disease test sites. This assay is designed to confirm true-positive Chlamydiazyme (CZ) specimens and to identify false-positive CZ reactions caused by cross-reacting bacteria. Cervical specimens were collected from 2,891 women. Chlamydia prevalence by tissue culture (TC) was 9.2% (266 of 2,891 specimens). Compared with TC, the sensitivity and specificity of CZ were 78.9% (210 of 266 specimens) and 98.2% (2,577 of 2,625 specimens), respectively. There were 48 CZ false-positive reactions. The direct fluorescent-antibody test (DFA) was positive for 31 of 48 false-positive reactions, indicating culture misses. Thus, when the standard was both TC and DFA, CZ sensitivity was 81.1% and CZ specificity was 99.3%. Of the 17 CZ-positive patients who were negative by both TC and DFA, 3 were negative on repeat CZ and 11 of 14 were identified as false positive by the confirmatory assay. The confirmatory test was positive for CZ-positive women who were positive by TC or DFA. Use of the confirmatory test, which increased the specificity to 99.9%, would increase confidence in positive CZ results and make the test more useful for screening populations with a low prevalence of C. trachomatis infection.

Adult↗
PubMed1990

Persistence of intrinsic neurones and possible phenotypic changes after extrinsic denervation of human respiratory tract by heart-lung transplantation.

Respiratory tract nerves have cell bodies outside (sensory, sympathetic) and inside (parasympathetic) the organ and contain bioactive peptides. These include calcitonin gene-related peptide and tachykinins (sensory nerves), vasoactive intestinal polypeptide (parasympathetic nerves), and neuropeptide with tyrosine (sympathetic nerves). Because transplantation interrupts the extrinsic nerve supply to the tissues, we have examined transplanted human respiratory tracts (n = 11) removed at retransplantation 2 to 42 months after the primary transplant in order to determine whether any nerves and peptide synthesis persist. As controls to establish nerve distribution in human respiratory tract, tissues were obtained from 10 lung resections and five autopsies. Cryostat sections were immunostained to demonstrate the general neural marker PGP 9.5, neuropeptides, and the catecholamine-synthesizing enzyme tyrosine hydroxylase. Nerves immunoreactive for PGP 9.5 were detected in all transplanted tissues. They were fewer in number overall than in control tissue, significantly so in epithelium of trachea and bronchus where they were present sparsely in only three cases. Nerves immunoreactive for tyrosine hydroxylase were significantly fewer in the transplants. Peptide-immunoreactive nerves were also reduced in number in the transplants, except for vasoactive intestinal polypeptide, which was only significantly changed in blood vessels in the lung. Ganglion cells immunoreactive for tyrosine hydroxylase and neuropeptide with tyrosine were seen in the transplanted tissues in five cases, but never in the control tissues. We conclude that whereas some nerves and neuropeptide synthesis persist after extrinsic pulmonary denervation, potentially significant changes also occur, including the appearance in intrinsic parasympathetic neurones of immunoreactivity for a catecholamine-synthesizing enzyme and a peptide normally found in sympathetic nerves.

Adult↗
PubMed1989

Extracellular matrix of sea urchin and other marine invertebrate embryos.

The extracellular matrix surrounding the sea urchin embryo (outer ECM) contains fibers and granules of various sizes which are organized in recognizable patterns as shown by ultrastructural studies, particularly stereoimaging techniques. The use of the ruthenium red method for retaining and staining the ECM, with modifications of the Luft (Anatomical Record 171:347-368, 1971) method for invertebrate embryos, allows for the clarification of certain structures, particularly fiber compaction in the interzonal region, and microvillus-associated bodies. The inner ECM in the sea urchin embryo includes the basal lamina and blastocoel matrix. Stereoimages show that the fibers which are loosely distributed in the blastocoel matrix become compacted around the periphery of the blastocoel to form the basal lamina. The ruthenium red method was also used on a number of marine invertebrate embryos and larvae, representing different phyla, to facilitate comparisons between their surface coats. The similarities observed in the specimens shown suggest that ECMs are widely found on marine invertebrate eggs, embryos, and larvae, and that they resemble vertebrate ECMs and may, therefore, have similar functions.

Animals↗
PubMed1989

Transmission of HIV to heterosexual partners of infected men and women.

Future heterosexual spread of HIV will in part depend on the efficiency of transmission from men to women and from women to men. We studied seventy-eight female sexual partners of men infected with HIV and 18 male sexual partners of infected women. Participants were interviewed concerning sexual practices, use of contraception and other risk factors for HIV infection. Fifteen out of 78 (19.2%) female partners and one out of eighteen (5.5%) male partners were seropositive for HIV antibody. All couples had practised vaginal intercourse. Seropositive female partners did not differ significantly from seronegative partners with regard to length of relationship, number of acts of vaginal intercourse, other sexual practices, stage of clinical disease in the index case, or numbers of other sexual partners in the last five years. In two women, seroconversion was documented after one act of unprotected sexual intercourse. The majority of infected female partners (eight out of 15) had sexual relationships with men who were asymptomatic and did not practice anal intercourse. Biological factors such as variability in infectivity of the index case and susceptibility of the contact, as well as behavioural variables may be important in determining transmission.

Adolescent↗
PubMed1988

Effects of passive immunization in patients with the acquired immunodeficiency syndrome-related complex and acquired immunodeficiency syndrome.

Infection with the human immunodeficiency virus type 1 (HIV-1) is usually followed by a vigorous immune response that temporarily protects against disease progression. After a variable asymptomatic period, acquired immunodeficiency syndrome (AIDS)-related complex (ARC) and AIDS develop in most infected individuals. We have demonstrated that healthy HIV-1-infected individuals have neutralizing antibodies and a high titer of antiviral antibodies. In contrast, AIDS patients have undetectable levels of neutralizing antibodies, low titers of antiviral antibodies, and, frequently, HIV p24 antigenemia. These observations prompted us to attempt passive immunization in ARC and AIDS patients. Ten consistently viral-antigen-positive patients (mean, greater than 6 months) were treated, resulting in sustained clearance of p24 antigen. Patients either maintained or increased their antiviral antibody titers. The raised titers result from increased antibody synthesis by the recipients. Circulating CD4+ cell counts were unchanged after 2 months. By the third month none of these patients remained in hospital. As this treatment was of minimal toxicity, it merits wider evaluation in ARC and AIDS patients.

AIDS-Related Complex↗
PubMed1988

Biennial survey of physician clinical nutrition training programs.

This is the third survey of physician clinical nutrition training programs. Current training programs were identified, descriptive information obtained, and training program content was compared with that recommended at the 1984 Conference on Clinical Nutrition Training. In general, goals as to the quantity of research, clinical, and teaching training are being met. Virtually all programs provide training in nutritional support activities. Most training programs are not as broad in scope of exposure to the less clinical aspects of nutrition nor to all the illness and age groups recommended by the 1984 conference. Consideration of broadening the scope of physician training programs or redefinition of training guidelines is warranted. A program-certifying agency may be helpful in identifying programs achieving certain minimal standards.

Curriculum↗
PubMed1987

Use of Karpas HIV cell test to detect antibodies to HIV-2.

Commercial enzyme-linked immunosorbent assays for HIV-1 infection often fail to detect antibodies to HIV-2. A simplified version of the HIV cell test detects antibodies to this new virus and enables typing of HIV infections. Since sera from 3 macaque monkeys infected with simian immunodeficiency virus gave weakly positive reactions, this test holds promise for discovering any further strains of HIV that may exist or evolve.

Animals↗