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Biomedical subjects

K Holbrook

Publications and source records attributed to K Holbrook.

14 recordsLinked to original sources
PubMed1993

The relationship of Chlamydia trachomatis infection and male infertility.

OBJECTIVES: Infertility affects at least 2 million couples in the United States. One third of infertility is attributed to male causes, but the etiology of most male infertility remains obscure. This study was designed to investigate the relationship between Chlamydia trachomatis and unexplained infertility in men. METHODS: Questionnaires and serum were collected prospectively from 52 case subjects (men from couples with explicitly defined idiopathic infertility) and 79 control subjects (first-time expectant fathers). RESULTS: Case subjects were significantly more likely than control subjects to be seropositive for antibody to C trachomatis at a titer of 1:64 or higher. By test of trend, higher titers were associated with higher odds ratios. Adjustment for age of either partner at initiation of pregnancy attempt, race, income, previous genitourinary symptoms or diagnoses, number of previous sexual partners, and barrier contraceptive use had no significant effect on the estimate of the odds ratio. One half of the men who were antibody positive had no history of genitourinary symptoms. CONCLUSIONS: Our results suggest an association between infection with C trachomatis in men and unexplained infertility and imply that infection is frequently asymptomatic.

Adult↗
PubMed1993

Sjögren-Larsson syndrome: technique and timing of prenatal diagnosis.

BACKGROUND: Sjögren-Larsson syndrome is an autosomal recessive disease with sequelae including ichthyosis, mental retardation, and spasticity. Although fetal skin biopsy has permitted prenatal diagnosis of Sjögren-Larsson syndrome in the late second trimester, it is accompanied by substantial risks, including fetal loss, premature labor, and detection at a gestational age close to the legal limit for pregnancy termination in most states. A new technique involving biochemical assay of cultured amniocytes for reduced levels of fatty alcohol:oxidized nicotinamide-adenine dinucleotide (NAD+)-oxidoreductase may allow earlier and less invasive detection of Sjögren-Larsson syndrome. CASE: A 38-year-old Lebanese woman, gravida 6, para 3, presented for prenatal diagnosis of Sjögren-Larsson syndrome following a history of two children born with the disease. At 19 weeks' gestation, multiple fetal skin biopsies were obtained by ultrasound-guided transabdominal percutaneous insertion of biopsy forceps. Histologic examination of the specimen revealed no evidence of Sjögren-Larsson syndrome. However, assay of fatty alcohol:NAD(+)-oxidoreductase in cultured amniocytes obtained at fetal skin biopsy showed a profound enzymatic deficiency. Additional fetal skin biopsies were obtained at 23.5 weeks' gestation, and histologic examination was positive for Sjögren-Larsson syndrome. The patient elected to terminate the pregnancy, and a subsequent autopsy on the fetus confirmed Sjögren-Larsson syndrome. CONCLUSION: This case demonstrates the limitations of histologic examination of fetal skin specimens for the diagnosis of Sjögren-Larsson syndrome and indicates the potential value of biochemical detection from fetal amniocytes. This new technique may allow earlier diagnosis of Sjögren-Larsson syndrome, is less invasive, and may be less psychologically traumatic for the patient if she elects to terminate the pregnancy.

Adult↗
PubMed1986

Cell surface carbohydrate changes during embryonic and fetal skin development.

Monoclonal antibodies to four type 2 chain carbohydrate antigens were used for immunohistochemical studies of embryonic and fetal skin. The antibodies detected N-acetyllactosamine and 3 fucosyl substitutes of this, blood group antigen H, Lex, and Ley. Periderm consistently stained for N-acetyllactosamine, Lex and Ley. The H antigen showed a variable and weak expression on peridermal cells from day 57 to day 84 estimated gestation age (EGA). After this period the H antigen was no longer expressed at peridermal cells. In the epidermis, N-acetyllactosamine was present on all cells until the age of 15 weeks EGA. After this period N-acetyllactosamine could only be demonstrated on basal cells after treatment with neuraminidase, indicating a masking of N-acetyllactosamine by sialic acid. The H antigen could not be demonstrated in the epithelium before 14 weeks EGA. At this time it appeared on spinous and granular cells in the epithelium. Lex stained both basal cells and intermediate cells positively, until keratinization around week 20 EGA. Ley is never expressed on basal cells. It is weakly expressed by intermediate cells from week 14 EGA. Our study demonstrates that N-acetyllactosamine is maximally expressed at the early stages of development, but may later be modified either by sialylation or fucosylation into blood group H or Lex, or by Ley substances, respectively. The orderly and well-defined changes observed during skin differentiation are in agreement with other studies, which have demonstrated the existence of chemically defined cell surface changes accompanying cell differentiation.

ABO Blood-Group System↗
PubMed1985

Characterization of a type VI collagen-related Mr-140 000 protein from cutis-laxa fibroblasts in culture.

The precise biochemical defects in connective-tissue metabolism that are responsible for the laxity of skin seen in the syndrome of cutis laxa are largely unknown. We have studied fibroblasts cultured from skin explants of a 2-year-old male with the syndrome. Electron-microscopic examination of this skin revealed decreased amounts of amorphous elastin and an increase in elastin-associated microfibrils. Although the cultured fibroblasts were similar to control skin fibroblasts in morphology, growth rate and total protein synthesis, there was a 4-6-fold increase in accumulation of a collagenous protein of Mr 140 000 in both the culture medium and in the cell layer. This protein was structurally distinct from collagen types I, III, IV, V and VIII. It was found to be related to a cell-surface-associated glycoprotein, GP140, by both antigenic cross-reactivity and peptide mapping. Our data support observations that GP140 is a precursor of at least one form of pepsin-extracted type VI collagen.

Cells, Cultured↗
PubMed1980

Calcium regulation of growth and differentiation of mouse epidermal cells in culture.

Modification of the ionic calcium concentration in the culture medium markedly alters the pattern of proliferation and differentiation in cultured mouse epidermal cells. When medium calcium is lowered to 0.05--0.1 mM, keratinocytes proliferate rapidly with a high growth fraction and do not stratify, but continue to synthesize keratin. The cells grow as a monolayer for several months and can be subcultured and cloned in low Ca++ medium. Ultrastructural examination of cells cultured under low Ca++ conditions reveals widened intercellular spaces, abundant microvilli and perinuclear organization of tonofilaments and cellular organelles. Desmosomes are absent. Epidermal cells growing as a monolayer in low Ca++ can be induced to terminally differentiate by adding calcium to the level normally found in the culture medium (1.2 mM). Cell-to-cell contact occurs rapidly and desmosomes form within 2 hr. The cells stratify by 1--2 days and terminally differentiate with cell sloughing by 3--4 days. After Ca++ addition, DNA synthesis decreases with a lag of 5--10 hr and is totally inhibited within 34 hr. In contrast, RNA and protein synthesis continue at 40--50% of the low Ca++ level at day 3, a time when many cells are detaching from the culture dish. Keratin synthesis is unaffected by the Ca++ switch.

Animals↗
PubMed1980

A familial cutis laxa syndrome with ultrastructural abnormalities of collagen and elastin.

A familial cutis laxa syndrome is reported in a mother and son. In addition, the son had Klippel-Tranaunay-Weber syndrome, which may be related to his underlying disorder. Ultrastructural examination of skin revealed previously recognized abnormalities of elastic tissue. In addition, abnormalities in collagen structure are demonstrated. The underlying defect in this disorder appears to result in abnormalities in both elastic tissue and collagen structure.

Adolescent↗
PubMed1980

Growth and differentiation of mouse epidermal cells in culture: effects of extracellular calcium.

The pattern of proliferation and differentiation in cultured mouse epidermal cells in markedly altered by modifying the ionic calcium concentration in the culture medium. When medium calcium is lowered from 1.44 mM to 0.05-0.1 mM, keratinocytes proliferate rapidly with a high growth fraction, do not stratify, but continue to synthesize keratin. The cells grow as a monolayer for several months and can be subcultured in low Ca++ medium. Ultrastructural examination of cells cultured under low Ca++ conditions reveals widened intercellular spaces with an absence of desmosomes. Microvilli are numerous, and tonofilaments and cellular organelles are organized perinuclearly. Epidermal cells growing as a monolayer in low Ca++ can be identified to terminally differentiate by adding calcium to the level normally found in the culture medium. Contact between cells occurs rapidly and desmosomes form within 2 hours. The cells stratify in 1-2 days and terminally differentiate in 3-4 days. After Ca++ addition, DNA synthesis decreases after a lag of 5-10 hours and is totally inhibited within 36 hours. In contrast, RNA and protein synthesis continue at 40-50% of the control level at Day 3, a time when many cells are detaching from the culture dish. Keratin synthesis is unaffected by the Ca++ switch. Manipulation of epidermal proliferation and differentiation by altering extracellular calcium levels should enhance the usefulness of epidermal cell cultures in the study of differentiation and carcinogenesis.

Animals↗
PubMed1978

Amniotic fluid fibronectin. Characterization and synthesis by cells in culture.

A glycoprotein immunologically related to plasma cold-insoluble globulin (CIG) and fetal skin fibroblast fibronectin has been purified from second-trimester human amniotic fluid. This protein (amniotic fluid fibronectin) migrated more slowly than CIG on sodium dodecyl sulfate gel electrophoresis and showed greater polydispersity which could result, at least in part, from heterogeneity in glycosylation. Cloned human amniotic fluid epithelioid and fibroblastic cells synthesized and secreted a protein with similar properties into the culture medium. Fibronectin was shown to be associated with the pericellular and extracellular matrix of cultured amniotic fluid cells by immunofluorescence, lactoperoxidase-catalyzed iodination, and labeling with ferritin-conjugated antibodies. The kinetics of secretion of the protein were consistent with its role as a matrix protein. We anticipate that amniotic fluid fibronectin will prove to be the same protein which elsewhere in the body is incorporated into connective tissues and basement membranes. Amniotic fluid could, therefore, serve as a convenient source of in vivo synthesized fibronectin for biological and structural studies.

Amniotic Fluid↗
PubMedDate not supplied

Rationale and methods for a statewide, prospective surveillance system for the identification and prevention of nosocomial infections.

Review of current methods of surveillance for nosocomial infection indicates that prospective surveillance of patients on a daily basis is the most accurate and valid method. In this paper, we detail such a method. Samples of hospitalized patients for surveillance are based on a fixed period of observation in each patient-care area. Data are collected on a detailed, standardized daily log that emphasize the recording of primary clinical data. Such a system is practical and is acceptable to infection control practitioners. Representative samples of patients are obtained. The utility of such a system for identifying preventable risk factors for the development and evaluation of programs of prevention is being tested in 12 acute-care hospitals in Rhode Island.

Cross Infection↗