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Biomedical subjects

J T Harvey

Publications and source records attributed to J T Harvey.

At least 19 recordsLinked to original sources
PubMed2005

Development of body oxygen stores in harbor seals: effects of age, mass, and body composition.

Harbor seal pups are highly precocial and can swim and dive at birth. Such behavioral maturity suggests that they may be born with mature body oxygen stores or that stores develop quickly during the nursing period. To test this hypothesis, we compared the blood and muscle oxygen stores of harbor seal pups, yearlings, and adults. We found that pups had smaller oxygen stores than adults (neonates 57%, weaned pups 75%, and yearlings 90% those of adults), largely because neonatal myoglobin concentrations were low (1.6+/-0.2 g% vs. 3.8+/-0.3 g% for adults) and changed little during the nursing period. In contrast, blood oxygen stores were relatively mature, with nursing pups having hematocrit (55%+/-0.2%), hemoglobin (21.7+/-0.4 g%), and blood volume (12.3+/-0.5 mL/kg) only slightly lower than the corresponding values for adults (57%+/-0.2%, 23.8+/-0.3 g %, and 15.0+/-0.5 mL/kg). Because neonatal pups had relatively high metabolic rates (11.0 mL O2/kg min), their calculated aerobic dive limit was less than 50% that of adults. These results suggest that harbor seals' early aquatic activity is primarily supported by rapid development of blood, with immature muscle oxygen stores and elevated use rates limiting aerobic diving ability.

Age Factors↗
PubMed2005

Contaminant loads and hematological correlates in the harbor seal (Phoca vitulina) of San Francisco Bay, California.

An expanding body of research indicates that exposure to contaminants may impact marine mammal health, thus possibly contributing to population declines. The harbor seal population of the San Francisco Bay (SFB), California, has suffered habitat loss and degradation, including decades of environmental contamination. To explore the possibility of contaminant-induced health alterations in this population, blood levels of polychlorinated biphenyls (PCBs), dichlorodiphenyldichloroethylene (DDE), and polybrominated diphenyl ethers (PBDEs) were quantified in free-ranging seals; relationships between contaminant exposure and several key hematological parameters were examined; and PCB levels in the present study were compared with levels determined in SFB seals a decade earlier. PCB residues in harbor seal blood decreased during the past decade, but remained at levels great enough that adverse reproductive and immunological effects might be expected. Main results included a positive association between leukocyte counts and PBDEs, PCBs, and DDE in seals, and an inverse relationship between red blood cell count and PBDEs. Although not necessarily pathologic, these responses may serve as sentinel indications of contaminant-induced alterations in harbor seals of SFB, which, in individuals with relatively high contaminant burdens, might include increased rates of infection and anemia.

Animals↗
PubMed2002

An analysis of the forces required to drag sheep over various surfaces.

Some occupational health and safety hazards associated with sheep shearing are related to shearing shed design. One aspect is the floor of the catching pen, from which sheep are caught and dragged to the shearing workstation. Floors can be constructed from various materials, and may be level or gently sloping. An experiment was conducted using eight experienced shearers as participants to measure the force exerted by a shearer when dragging a sheep. Results showed that significant changes in mean dragging force occurred with changes in both surface texture and slope. The mean dragging forces for different floor textures and slopes ranged from 359 N (36.6 kg) to 423N (43.2 kg), and were close to the maximum acceptable limits for pulling forces for the most capable of males. The best floor tested was a floor sloped at 1:10 constructed of timber battens oriented parallel to the path of the drag, which resulted in a mean dragging force 63.6N (15%) lower than the worst combination.

Animal Husbandry↗
PubMed2000

Immunohistochemical evidence for estrogen receptors in meibomian glands.

PURPOSE: To look for sex hormone receptor distribution in three structures contributing to the normal human tear film: the conjunctiva, the accessory lacrimal glands, and the meibomian glands. DESIGN: An immunohistochemical study. TISSUES AND CONTROLS: Forty-one upper eyelid specimens were collected from 15 male and 26 female patients (age range, 1.5-85 years) during blepharoptosis surgery via posterior tarsoconjunctival mullerectomy (Fasanella-Servat or Gavaris). In addition, control sections of histologically normal breast, prostate, and skin tissue were obtained. METHODS: Immunohistochemical staining using mouse monoclonal antibodies against estrogen, progesterone, and androgen receptors was performed on all tissues and controls. Quantitation of the receptors was performed and expressed as percentage nuclear positivity. Specimens were divided into three groups based on the age of the patient: <12 years (n = 9); 18-55 years (n = 1); >55 years (n = 12). RESULTS: Forty-one specimens contained conjunctiva. All were negative for estrogen, progesterone, and androgen receptors. Twenty-four specimens contained accessory lacrimal glands of Wolfring. All were negative for the three receptors. Twenty-two specimens contained meibomian glands. All were positive for estrogen receptors; one was positive for progesterone receptors and one for androgen receptors. Using Minitab statistical software (Minitab Inc. State College, PA), analysis of variation revealed no statistical difference between sexes or between age groups studied. The sebaceous glands of skin were uniformly positive for androgen receptors. Sebaceous glands of the face and scalp (3 of the 15 skin samples) were also positive for estrogen receptors. CONCLUSIONS: Estrogen receptors are present in the meibomian glands of the upper eyelid. Unlike sebaceous glands elsewhere on the skin, the meibomian glands lack androgen receptors. Estrogen receptors may play a role in modulation of the lipid layer of the tear film, and their activity may be linked to meibomian gland dysfunction and dry eye syndrome.

Adolescent↗
PubMed1999

Distribution of adrenergic receptor subtypes in the retractor muscles of the upper eyelid.

PURPOSE: To identify adrenergic receptor subtypes and their relative distribution in the retractor muscles of the upper eyelid, the levator palpebrae superioris, and the Müller muscle. The pattern of distribution of these receptors in the Müller muscle was further compared in patients with dysthyroid eyelid retraction and in normal subjects. METHODS: Müller muscle specimens were collected from 19 patients undergoing ptosis correction and from 8 patients undergoing repair of dysthyroid eyelid retraction. Immunohistochemical staining for alpha 1-, alpha 2-, beta 1-, and beta 2-adrenergic receptors was performed using antihuman rabbit polyclonal antibodies. RESULTS: alpha 2-Adrenergic receptors were the predominant subtype in the Müller muscle, and beta 1-adrenergic receptors were the predominant subtype in the levator muscle. There was no significant difference in the staining pattern between specimens collected from patients with dysthyroid eyelid retraction and those from normal subjects. CONCLUSIONS: The interaction between the alpha 2 and beta 1 receptors in the upper eyelid retractor muscles may be important in the control of the upper eyelid position and may contribute to the development of dysthyroid eyelid retraction. Specific alpha 2 antagonists could be developed and may be effective pharmacologic agents for the treatment of eyelid retraction.

Eyelid Diseases↗
PubMed1999

Characterization of adrenergic receptors in the accessory lacrimal glands of the upper eyelid.

PURPOSE: To identify the histologic location as well as the exact subtype of adrenergic receptors in the accessory lacrimal glands of the upper eyelid. METHODS: Upper eyelid specimens were collected from 19 patients undergoing routine blepharoptosis correction via a posterior tarsoconjunctival mullerectomy. Immunohistochemical staining using polyclonal antibodies against human alpha 1, alpha 2, beta 1, and beta 2 receptors was performed on all specimens. RESULTS: beta 1 receptors were the predominant adrenergic receptor subtype in the glands of Wolfring. CONCLUSIONS: The presence of beta 1 receptors in the accessory lacrimal glands of the upper eyelid may suggest a possible role for selective beta 1 agonists in the treatment of keratitis sicca.

Blepharoptosis↗
PubMed1998

Sclerosing sweat-duct carcinoma (malignant syringoma) of the upper eyelid: a patient report with immunohistochemical and ultrastructural analysis.

Sclerosing sweat-duct carcinoma or malignant syringoma is a rare eyelid tumor. The authors report the first patient with sclerosing sweat-duct carcinoma involving the upper eyelid and present its immunohistochemical and ultrastructural features. The clinical features and the histopathologic and ultrastructural findings that distinguish this tumor from its benign counterparts are discussed. Sclerosing sweat-duct carcinomas are slow growing but locally invasive neoplasms that have a propensity to recur. Wide and deep surgical excision with frozen section evaluation of margins is recommended.

Biomarkers, Tumor↗
PubMed1998

Sensitivity and specificity of the diagnosis of periocular lesions by oculoplastic surgeons.

BACKGROUND: A few studies have assessed the sensitivity of ophthalmologists in diagnosing periocular lesions. However, no study has assessed their diagnostic specificity or the degree to which they overdiagnose various lesions. We performed a study to determine the sensitivity and specificity of oculoplastic surgeons' preoperative diagnoses of common and uncommon periocular lesions. METHODS: Using the patient records of four oculoplastic ophthalmologists, we reviewed all charts documenting periocular surgery in which lesions were excised and sent for biopsy. For each of 358 cases we recorded the preoperative diagnosis as listed by the surgeon and the postoperative diagnosis as reported by the pathologist. Each preoperative diagnosis was then scored as correct or incorrect. The relative number of each type of lesion was determined, and the ophthalmologists' sensitivity and specificity were calculated. RESULTS: The sensitivity and specificity for the eight most frequently lesions were (in order of frequency) basal cell carcinoma 92.1% and 81.6% respectively, papilloma 81.6% and 66.0%, cyst 66.7% and 69.7%, nevus 53.6% and 75.0%, seborrheic keratosis 27.8% and 71.4%, chalazion 93.3% and 100.0%, squamous cell carcinoma 33.3% and 55.6%, and xanthelasma 100.0% and 76.9%. The values for melanoma were 50.0% and 28.6%, for sebaceous gland carcinoma 0.0% and 100.0%, and for uncommon lesions (nonspecific inflammation, actinic keratosis, granuloma, cavernous hemangioma, folliculitis, benign sweat gland tumour, eccrine hidrocystoma and collagenous tissue) 27.8% and 57.1%. The overall accuracy in lesion identification was 70.0%. INTERPRETATION: Although ophthalmologists have excellent diagnostic sensitivity and specificity for some types of lesion, such as basal cell carcinoma and chalazion, the identification of other lesion types, such as cyst, squamous cell carcinoma and possibly melanoma and sebaceous gland carcinoma, is less optimal.

Adolescent↗
PubMed1995

Transcanalicular removal of silastic nasolacrimal tubes.

Removal of nasolacrimal tubes is often an awkward procedure when performed transnasally, especially in children and apprehensive adults. We evaluated in a prospective fashion the transcanalicular route to retrieve nasolacrimal tubes. Overall, this technique was well tolerated by patients and easy to perform. Tube breakage during removal may be a complication.

Adult↗
PubMed1995

Blastogenesis and interleukin-2 receptor expression assays in the harbor seal (Phoca vitulina).

Two in vitro functional assays were developed to evaluate mitogen-induced responses of peripheral blood mononuclear leukocytes (PBML) from free-ranging harbor seals, Phoca vitulina. Lymphocyte proliferation was measured by a standard blastogenesis assay following optimization of culture conditions including mitogen concentration, cell density, and incubation time. These optimized parameters, with the exception of incubation time, were subsequently employed to measure lymphocyte activation by analytical flow cytometry using fluorochrome-based identification of cell surface interleukin-2 receptor (IL-2r) expression. Baseline values established for free-ranging harbor seals had extensive animal variability; there was evidence that the samples were derived from a group of animals with a normal distribution. Positive correlations were observed between blastogenesis assays, and between blastogenesis and activation assays, when using pokeweed or concanavalin A as the stimulus. However, no relationship was found in the expression of the IL-2r induced by these mitogens. This result supports the contention that the two mitogens stimulate different lymphocyte subpopulations. This was observed only with the IL-2r expression assay because of its unique ability to measure the number of T lymphocytes initially activated rather than the ultimate number of progeny cells identified by blastogenesis. Both assays, used concurrently, should provide a more comprehensive representation of lymphocyte competence and serve as a measure of animal health.

Animals↗
PubMed1992

Tests for contralateral pseudoretraction in blepharoptosis.

Pseudoretraction of the contralateral upper eyelid has long been recognized as a clinical phenomenon in certain patients with unilateral ptosis. In this prospective study of 30 patients with ptosis, we used two commonly used tests for pseudoretraction, the digital "lift" and "closure" tests. We also describe two new adaptations, the "lift and release" and "closure and release," which enhance these basic tests. The incidence of pseudoretraction in unilateral ptosis was found to be 66.7% and the test with the highest positive yield was the "closure test" (66.7%). The use of clinical tests for pseudoretraction, including the "release" maneuvers, are recommended as part of routine preoperative assessment of blepharoptosis.

Adolescent↗
PubMed1991

Long-term placement of silastic nasolacrimal tubes.

We retrospectively reviewed the complication rate associated with silastic tube intubation in the treatment of congenital and acquired obstructions of the lacrimal system in 82 patients with a follow-up of 3 to 66 months. Complications included tube prolapse, extrusion or breakage, punctal erosion, conjunctival irritation, intranasal discomfort, and tube inspissation with mucoid debris ("dirty tubes"). The rate was highest in the first 3 months (41%); it decreased to less than 10% after 6 months. Based on these findings, we recommend that silastic nasolacrimal tubes be regarded as semi-permanent devices which may safely be left in place for years.

Adolescent↗
PubMed1991

Modified levator aponeurosis recession for upper eyelid retraction in Graves' disease.

Recession of the levator aponeurosis has proved to be an excellent operation to correct upper eyelid retraction in Graves' disease. Harvey and Anderson's original description included recession of the levator aponeurosis along its entire width and complete extirpation of Müller's muscle. In a modification of the technique, we recess only the lateral two thirds of the levator/Müller's complex. Also, rather than excising Müller's muscle, we simply recess it en bloc with the levator aponeurosis. The lateral horn of the levator is cut, as previously advocated, to relieve the marked temporal elevation of the eyelid characteristic of Graves' lid retraction. This modified procedure provides good upper lid lengthening, with less surgical manipulation, less bleeding, and avoids medial over-corrections. Of 22 upper lids (12 patients) treated with this procedure, 19 (86.3%) were considered "good" after the operation.

Adult↗
PubMed1991

A modification of the lateral tarsal strip procedure with resection of orbicularis muscle for entropion repair.

The lateral tarsal strip procedure addresses lateral canthal laxity, but is inadequate in some patients with entropion who have overriding of the orbicularis muscle. We describe our technique, which incorporates resection of the hypertrophied orbicularis. We have used this modification of the lateral tarsal strip procedure in 21 eyelids (15 patients) with excellent results.

Adult↗