Biomedical subjects

W H Knobloch

Publications and source records attributed to W H Knobloch.

At least 19 recordsLinked to original sources

PubMed1990

Dental abnormalities as a component of the Laurence-Moon-Bardet-Biedl syndrome.

Previous reports have described the diversity of the phenotypic expression of the Laurence-Moon and Bardet-Biedl syndrome. This report describes two brothers whose features include the previously unreported defect of oligodontia in addition to retinitis pigmentosa, hypogenitalism, strabismus, short stature, and developmental delay. The reports over the last century have emphasized the varied expression from family to family and even differences among members of the same family. This report broadens the already pleomorphic nature of this syndrome.

Abnormalities, Multiple↗

PubMed1989

Treatment of cytomegalovirus retinitis with intravitreal ganciclovir. Long-term results.

Long-term management of cytomegalovirus (CMV) retinitis by intravitreal injection of ganciclovir was evaluated in ten patients with acquired immune deficiency syndrome (AIDS). Patients were unable to tolerate systemic ganciclovir because of severe neutropenia (8 cases), catheter-induced sepsis (1 case), or the need to continue therapy for human immunodeficiency virus (HIV) with zidovudine (ZDV) (1 case). All patients had a favorable response to initial treatment. Cytomegalovirus retinitis progressed in four fellow eyes in which treatment was deferred. Vision improved or remained stable in all but one eye. Patients were followed for a mean of 4 months and received an average of 16.6 intravitreal injections in each eye. Relapse occurred late in the course while on maintenance treatment in five eyes (33%). There was no evidence of toxicity from repeated intravitreal injections. Treatment was very well tolerated. The only severe complication in a total of 249 injections was a single case of Staphylococcus epidermidis endophthalmitis which responded to intravitreal antibiotic treatment. Intravitreal ganciclovir is an effective alternative to systemic ganciclovir in those patients with severe neutropenia and in those patients who desire to remain on systemic ZDV.

Acquired Immunodeficiency Syndrome↗

PubMed1989

Genetic linkage analysis of hereditary arthro-ophthalmopathy (Stickler syndrome) and the type II procollagen gene.

Hereditary arthro-ophthalmopathy (AO), or Stickler syndrome, is a dominantly inherited disorder characterized by vitreo-retinal degeneration and frequently accompanied by epiphyseal dysplasia and premature degenerative joint disease. Three large families with AO were analyzed for clinical manifestations of the disease and for coinheritance of the genetic defect with RFLPs in the type II procollagen gene (COL2A1). Genetic linkage between AO and COL2A1 was demonstrated in the largest family, with a maximum LOD score of 3.52 at a recombination distance of zero. Data from a second family also supported linkage of AO and COL2A1, with a LOD score of 1.20 at a recombination distance of zero. These results are consistent with the conclusion that mutations in the COL2A1 gene are responsible for AO in these two families. In a third AO family, however, recombination between AO and COL2A1 occurred in at least one meiosis, and the data were inconclusive with respect to linkage.

Chromosomes, Human, Pair 12↗

PubMed1988

Progression of diabetic retinopathy after pancreas transplantation for insulin-dependent diabetes mellitus.

We studied the effect of successful pancreas transplantation and consequent normoglycemia (mean total hemoglobin A1, 7.0 percent; range, 5.8 to 8.3) on visual function and diabetic retinopathy in 22 patients with Type I diabetes mellitus (study group). Sixteen similar patients in whom pancreas transplantation had been unsuccessful (mean total hemoglobin A1, 12.0 percent; range, 8.0 to 18.0) served as a control group. The majority of patients in both groups had advanced proliferative retinopathy. At a mean follow-up of 24 months we found no significant difference between the groups in the rate of progression of retinopathy, expressed as a score. Success of the transplantation did not prevent progression of retinopathy across the range of retinopathy studied. Progressive retinopathy was observed more commonly in patients with low retinopathy scores (nonproliferative or mild proliferative retinopathy) at base line in both the study group (13 of 17 eyes, or 76 percent) and the control group (7 of 12 eyes, or 58 percent). Further analysis suggested the possibility that after three years of euglycemia, the study group had less deterioration than the control group, particularly in eyes with advanced retinopathy. We observed no difference in the rate of loss of vision between the two groups. This study provides evidence that pancreas transplantation and subsequent normoglycemia neither reverse nor prevent the progression of diabetic retinopathy.

Adolescent↗

PubMed1988

Hermansky-Pudlak syndrome. Ophthalmic findings.

Prospective ophthalmic evaluation was performed in 20 individuals with Hermansky-Pudlak syndrome, a type of oculocutaneous albinism with an associated deficiency of dense bodies in platelets. The extent of visual impairment and the possible relationship to the degree of hypopigmentation were studied. All patients showed nystagmus, visual acuity ranged from 20/60 to 20/400, and correction of refractive error provided a mild improvement in vision. Iris pigmentation varied in amount and did not correlate with the visual acuity measurement. Foveal hypoplasia was found in all patients, but variability in macular transparency and vascular architecture was noted. Visual-evoked potentials performed in 11 patients demonstrated excessive decussation of optic fibers. Recognition of this form of oculocutaneous albinism is important because of the associated pulmonary, gastrointestinal, renal, and cardiac manifestations of Hermansky-Pudlak syndrome.

Adolescent↗

PubMed1986

Timing of vitrectomy for active proliferative diabetic retinopathy.

Eyes with active proliferative diabetic retinopathy with dense sub-hyaloid hemorrhage and significant visual loss represent an appropriate indication for prompt vitrectomy. Twenty-six such eyes in 22 patients were operated. The results are compared to 49 diabetic eyes undergoing vitrectomy for other complications of diabetic retinopathy. The results demonstrated both an improved anatomic success rate (85% compared to 73%) and a higher rate of reading visual function (54% compared to 18%) in the early vitrectomy group, substantiating the study hypothesis.

Adult↗

PubMed1986

Partial trisomy 6q and bilateral retinal detachment.

An eight-year-old boy with trisomy 6q13----q21 is described with growth retardation, severe mental retardation, unusual facies, cleft palate, joint contractures and bilateral retinal detachment. To the authors' knowledge, this is the first case in which such an association has been recorded.

Child↗

PubMed1986

Vitrectomy and endolaser for complications of proliferative diabetic retinopathy.

Argon laser endophotocoagulation capability during vitrectomy surgery represents a significant technological advance. This report details the initial experience with this technique at the University of Minnesota in 18 patients with particularly high-risk complications of proliferative diabetic retinopathy. Overall, 13 of the 18 eyes (72%) were stabilized anatomically. In comparison with preoperative levels, visual acuity improved in 11 eyes, remained unchanged in 1 eye and deteriorated in 6 eyes. The technique is used intraoperatively to treat existing, iatrogenic or purposeful retinal breaks and to do panretinal scatter therapy to reduce the incidence of postoperative neovascular complications affecting either the anterior or posterior segment of the globe.

Adolescent↗

PubMed1985

Vitrectomy for double penetrating ocular injuries.

During the five-year period from 1977 to 1982, 15 consecutive patients with double penetrating ocular injuries were treated at the University of Minnesota. The 13 males and two females ranged in age from 5 to 38 years. Four patients had bilateral involvement. Vitrectomy techniques were used to stabilize the eyes and prevent or treat retinal detachment in 18 eyes. One eye was enucleated. Anatomic success was achieved in 11 eyes and visual success (visual acuity of 5/200 or better) in ten eyes. Surgical success was related to initial visual acuity, extent of vitreous hemorrhage, and the ability of the surgeon to excise completely the vitreous from the circumference of the exit wound.

Adolescent↗

PubMed1985

Eye findings in twins reared apart.

Twenty-six pairs of reared apart twins were evaluated ophthalmologically. Included were 18 monozygotic pairs and eight same sex dizygotic pairs. A high concordance of C/D ratios and esotropia was evident. Though reared apart, three pairs of esotropic MZ twins had almost simultaneous onsets of diagnosis and treatment for their strabismus. Genetic influence on the development of refractive errors was evident by the greater similarity of the refractions in MZ twins when compared to DZ twins.

Adult↗

PubMed1984

Retinal vascular changes in malignant melanoma of the choroid.

A review of fluorescein angiograms from 41 patients with malignant melanoma of the choroid showed that 11 patients (27%) had evidence of retinal vascular abnormalities. Abnormal retinal capillaries were found in eight cases, areas of capillary nonperfusion in seven cases, and microaneurysms in four cases. Lipid exudation, retinal neovascularization, and arteriovenous communication were noted in one case each. Histopathologic studies in eight cases showed extensive degeneration of the overlaying retina in all eight cases and extension through Bruch's membrane by the tumor in four cases. Abnormal capillary architecture was demonstrated by trypsin digest preparations from four cases.

Adult↗

PubMed1983

Rips in the pigment epithelium.

Rips of the retinal pigment epithelium (RPE) are an uncommon complication of RPE detachment. We suspect that RPE rips are the result of tractional forces acting along the margin of the detached RPE, and that the risk of tearing is greatly enhanced by laser photocoagulation. Rips of the RPE have a characteristic clinical and angiographic appearance. There is a slight tendency for rips to occur bilaterally. Rips may be difficult to recognize because of healing of the RPE defect. This unusual clinical entity may, in fact, be more common than was previously appreciated.

Aged↗

PubMed1983

Pseudophakic retinal detachment.

The clinical findings, surgical techniques, anatomic results and visual recovery in 71 pseudophakic and 71 aphakic eyes with retinal detachment repaired concurrently were compared. Preoperative visibility of the peripheral retina was significantly reduced in the pseudophakic group. Intraoperative identification of retinal breaks was useful for the pseudophakic eyes. The surgical techniques used in the two groups were similar. Anatomic success was achieved in 65 pseudophakic eyes (92%) and 63 aphakic eyes (89%); however, the visual recovery after a mean follow-up period of 18 months was poorer in the pseudophakic group, only 35 (54%) of which, compared with 39 (62%) of the aphakic group, had a final best-corrected visual acuity of 6/15 or better.

Aged↗

PubMed1982

Autosomal recessive vitreoretinopathy and encephaloceles.

We conducted a ten-year follow-up of an unusual pedigree with an autosomal recessive vitreoretinal degeneration, severe myopia, and congenital encephalocele. All five affected members (four girls and one boy) also had early, recurrent bilateral detachments. Color vision testing disclosed an acquired tritan dyschromatopsia and electroretinography showed subnormal photopic and scotopic amplitudes, delayed b-wave implicit times and 30-Hz flicker-phase relations, and absent scotopic b-wave oscillations.

Child↗

PubMed1982

Cryoretinopexy for proliferative diabetic retinopathy.

Cryoretinopexy can be used in the management of proliferative diabetic retinopathy. Indications include retinal neovascularization following photocoagulation or with opaque media, and anterior segment neovascularization. Of the six eyes in five patients treated with transconjunctival cryoretinopexy only one demonstrated regression of neovascularization; in this group, vision improved in two eyes, remained the same in three eyes and decreased in one eye. Of the 14 eyes in 14 patients treated with anterior transscleral cryoablation 5 demonstrated regression of posterior segment neovascularization and 2 demonstrated regression of anterior segment neovascularization; in this group, vision improved in 3 eyes, remained the same in 2 eyes and decreased in 9 eyes. No complications were associated with transconjunctival therapy, whereas uveitis (in 14 eyes), vitreous hemorrhage (in 2 eyes) and traction retinal detachment (in 5 eyes) were noted following transscleral therapy. Further studies are required to determine the risk/benefit ratio of cryoablation for proliferative diabetic retinopathy.

Adult↗

PubMed1981

Electrophysiologic changes in chronic pars planitis.

We studied 13 patients, six males and seven females, ranging in age from 14 to 53 years, with chronic pars planitis and a form of secondary retinal degeneration. All had experienced visual blurring but none had significant pain. Nine of the 13 had some disturbance in night vision. Visual acuity had decreased in three patients (in one because of cataract, in one because of cystoid macular degeneration, and for unknown reasons in the third), increased in two patients (because of improvement in cystoid macular edema), and remained stable in eight. There were electrophysiologic abnormalities, consisting of delayed B-wave implicit time, abnormal response to 30-Hz flicker, and reduced B-wave oscillations, in almost every patient. Our finding suggested that pars planitis is a vitreoretinal disorder rather than an inflammatory disease of the uveal tract.

Adolescent↗

PubMed1980

Postpartum Candida endophthalmitis.

Two patients experienced endogenous Candida endophthalmitis after childbirth. One case was successfully treated with vitrectomy and intravitreal injection of amphotericin B. Although rare, Candida endophthalmitis must be included in the differential diagnosis in the postpartum patient with visual symptoms.

Adult↗

PubMed1980

Histocompatibility antigen frequencies in diabetic retinopathy.

We studied the histocompatibility antigens A and B in 300 insulin-dependent diabetics: 200 had proliferative retinopathy and 100 did not. The two groups were matched for known duration of diabetes and other clinical features. In both groups the frequencies of HLA-B8, HLA-B18, and HLA-B8/HLA-B15 were significantly higher, and those of HLA-B7 and HLA-B12 were significantly lower than in healthy controls. The patients with proliferative retinopathy were significantly less often positive for HLA-B7 (X2 = 10.0; Pc < .03) than patients with nonproliferative retinopathy. When both groups were stratified for age at diagnosis, there were additional differences. HLA-B15 was significantly more frequent in the proliferative retinopathy group with age at diagnosis between 15 and 40 years (nonproliferative retinopathy = 16.4%; proliferative retinopathy = 39.4%; X2 = 7.89, Pc < .03; relative risk = 3.32) and HLA-B7 significantly less frequent (nonproliferative retinopathy = 23.6%; proliferative retinopathy = 5.6%; X2 = 8.0, Pc < .03; relative risk = 0.19). These differences in histocompatibility frequencies between patients with and without proliferative retinopathy indicate a genetic contribution to diabetic retinopathy.

Adolescent↗