Determination and in vivo characterization of the basic replicon of natural plasmids of Methylomonas clara

The basic replicon of the endogenous Methylomonas clara plasmid pBE-2 and its derivatives was defined to a region of 2.7 kb by in vivo deletions and conjugative transfer experiments using Escherichia coli-M. clara hybrid plasmids. Origin activity was found to be confined to a maximal length of 1.3 kb. The origin consists of two fragments which can be separated more than 4 kb by the integration of foreign DNA fragments without loss of function. A fragment having a maximum size of 2.1 kb supports in trans replication initiation at the origin. In addition, two incompatibility determinants were revealed, one localized in the origin fragment and the other outside the origin. Incompatibility between two basic replicons of the natural M. clara plasmids can be overcome by the integration of one of them in the compatible IncP plasmid R68-Kms. No homology was found between the plasmid basic replicon and the chromosomal DNA of M. clara.

[Central areolar choroid dystrophy. Report of involvement of 3 generations]

Central areolar chorodial atrophy was first classified as a hereditary disease by Sorsby in 1935. The mode of inheritance can be both autosomal recessive and autosomal dominant. The authors present a case with autosomal dominant inheritance affecting three generations.

Ocular perfusion pressures in different types of glaucoma

It is widely accepted that a disturbed blood supply of the optic disc may cause (in addition with an increased intraocular pressure) optic nerve fibre damage. Therefore we measured ocular perfusion pressures in 79 healthy subjects. In 18 patients with low tension glaucoma, in 27 patients suffering from ocular hypertension and in 49 glaucoma (OAG) patients. For measuring perfusion pressures we used the technique of oculo-oscillo-dynamography (OODG) as described by Ulrich. Additionally we measured intraocular pressure and systemic blood pressure. In OODG the IOP is simultaneously increased in both eyes by application of a suction cup. After increase of the IOP the negative pressure in the suction cup is slowly and linearly decreased. During this decrease the pulse-depending oscillations of each eye are recorded on a strip-chart-recorder. By means of this method retinal and ciliary perfusion pressures can be separated. As a result we could show that mean arterial blood pressure and systolic retinal perfusion pressure were comparable and not statistically significantly different between the groups examined. The systolic ocular perfusion pressures in patients with low tension glaucoma showed a highly statistically significant reduction compared with the other groups. Between healthy subjects, OAG-patients and patients suffering from ocular hypertension there was no difference in systolic ciliary perfusion pressure detectable.

[Ocular hemodynamics following local administration of clonidine]

The influence of topically applied clonidine 0.125% on ocular hemodynamics was investigated in ten patients with open-angle glaucoma and ten healthy volunteers, using a new, differentiated method. Ocular perfusion pressures were determined by Ulrich's method of oculo-oscillodynamography. Following monocular application of clonidine 0.125% eye drops a clear decrease in systemic blood pressure and a somewhat less pronounced reduction of ocular perfusion pressure was observed in both groups of patients. The reduction in ocular perfusion pressures was higher in the eye after drop application than in the untreated control eye. It must therefore be assumed that clonidine 0.125% eye drops have a local perfusion pressure-reducing effect in addition to their systemic effect.

[Ocular hemodynamics following suction cup oculopression]

In the study reported here the authors investigated the influence on ocular perfusion pressures of suction-cup oculopression, a procedure which permits oculopression without orbital compression. Patients over 50 years of age were examined before cataract extraction. Ulrich's method of ocular oscillodynamography was used to determine ocular perfusion pressures. A Mikuni and Yoneyama suction-cup dynamometer was applied for suction-cup oculopression. Ocular hypotonia following suction-cup oculopression was adequate and comparable to that achieved by other oculopression methods. After oculopression a significant increase in ocular perfusion pressures (retinal, ciliary, and diastolic) was found. However, ocular blood pressure remains constant after oculopression. Moreover, the increase in ocular perfusion pressure could not be explained by oculocardiac reflexes, because there was no change in systemic arterial blood pressure. It must be assumed, therefore, that the increase in ocular perfusion pressures is caused by a lowering of resistance, i.e., a drop in intraocular pressure.

[Clinical experiences with a therapeutic collagen contact lens. Initial results]

Clinical treatment with a self-dissolving collagen bandage lens was studied in 29 eyes. The lens was used in ten eyes with corneal abrasion, seven with lamellar perforating corneal injuries, six with corneal abrasion following foreign body removal, two after pterygium surgery, in one corneal abrasion caused by radiation, in two eyes with photoelectric keratoconjunctivitis, and in one patient with a trophic-sterile corneal ulcer. In all cases wearing comfort was excellent and no allergic reactions were observed. The patients with corneal abrasions experienced a significant reduction in pain immediately after application of the lens, so that no pressure patch was necessary. In the cases with corneal abrasion due to radiation and trophic-sterile ulcer, re-epithelialization occurred more rapidly than with the customary treatment.

[Perforating eye injuries caused by darts]

Four perforating eye injuries sustained by children playing with darts are analyzed. The injuries occurred within a period of 17 months. All the patients had minor injuries of the anterior segment and severe injuries in the posterior segment, such as vitreous hemorrhages and double perforations. Precautions should be taken to prevent such injuries: games involving darts are not suitable for children.

[Gelatinous tear substitutes and nonspecific eye ointments in the critical care unit and in perioperative use]

The effect of Vidisic (a new jelly artificial tear solution) and an ointment basing on Dexpanthenol on the tear production and the tear film stability was studied both on patients in the intensive care units (ICU) and during operations. In 10 relaxed and ventilated patients of the ICU there was no significant change in the tear production after application of either therapy. In 30 patients, undergoing surgery in endotracheal anaesthesia, the break-up-time and the test according to Schirmer were measured pre- and postoperatively. Like in the ICU-patients no difference in tear production could be found. Regarding the stability of the precorneal tear film however Vidisic was more effective than ointment basing on Dexpanthenol. Especially this clear jelly artificial tear solution allowed in contrast to the ointment a permanent and reliable judgement of the pupillary reaction. In addition the patients felt more comfortable with Vidisic.

[Corneal contact time of artificial tear solutions]

In 30 subjects without ophthalmological disease the corneal contact time of a new artificial polyacrylic-based tear gel (Vidisic, produced by Dr. Mann, Berlin) was compared with a well-known artificial polyvinyl alcohol-based tear solution. The Vidisic concentration remained in the corneal tear film 7 times longer than the substance it was compared with. In a second study including 7 normal subjects and 5 patients with keratoconjunctivitis sicca, the influence of Vidisic on break-up time (BUT) and the Schirmer test was demonstrated. It was found that tear secretion improved for 2-4 hours (Schirmer test) and the stability of the tear film (BUT) improved for about 6 hours with Vidisic. These results suggest that application of Vidisic four times a day is sufficient for efficatious therapy even in cases of severe keratoconjunctivitis sicca.

[Diagnostic tests in the evaluation of the tear film]

Critical appraisal of the most important testing methods for diagnosing normal and disturbed stability of the tear film meniscus. Only a carefully compiled history, a thorough inspection of the eye and several tests to determine the type and severity of the disorder can provide information about the disturbed stability of the tear film meniscus.

[Treatment of dry eye with a new gel in eyedrop form]

Vidisic, a liquid gel derived from a polymerisate of acrylic acid for the treatment of dry eyes, was tested for 3 months in an open prospective study in 55 patients with severe dry eye. Vidisic spreads well over the cornea and conjunctiva and does not cause streaks. Compared with other tear substitutes so far available, Vidisic has a much longer viability, so that no more than 3 or 4 drops a day are necessary. Also, Vidisic is better tolerated and more effective. Moreover, there was a significant improvement, both subjectively and objectively, in the patients' conditions.

Cartilage choristoma of the eye

A young girl had a rigid, white tumor that penetrated the sclera. It was partially resected, and histopathologic study demonstrated choristoma of elastic cartilage.

[The malignancy of choroidal melanomas (author's transl)]

In the destruction of choroidal melanomas with conservation of the globe two clinical parameters, the size and growth-rate of the tumor, are especially important. The malignancy can be determined from these two parameters. It is important to know that neoplasms metastasize when they are composed of more than 400 cells (10 doubling times). However, at this early stage clinical diagnosis it rarely possible. As a rule, the tumor cannot be diagnosed until it reaches a size of 5 mm (27 doubling times). Metastases must be at least 10 mm in diameter (38 doubling times) to be recognized. In the case of the fast-growing choroidal melanomas it can therefore be calculated that the formation of metastases reaches a peak after a period of three to four years, assuming that diagnosis is made as early as possible. In 64 patients followed up for five years we found that the more numerous the number of mitoses in the tissue are, the higher the mortality is and the sooner the patients die. According to our results the most important clinical parameter in the assessment of choroidal melanoma, apart from the size of the tumor, is the estimation growth-rate, as indicated by the number of mitoses.

[Radiation accidents affecting the eye and their treatment (author's transl)]

Eye injuries which can occur as a result of radiation accidents of leaks in nuclear power plants are described and their treatment discussed. The trauma may be due to mechanical or thermal influences or the result of exposure to chemicals or radioactivity. After stopping the blepharospasm careful inspection of the conjunctiva is mandatory. If the bulbus is intact, rinsing with a pulsating water jet (Waterpik) is recommended, while if it is perforated primary operative treatment of the injury must be performed before radiation damage sets in. It is pointed out that the special medical centers for the treatment of radiation damage are equipped for ophthalmic surgery.

[Studies relating to tear film stability (author's transl)]

Basic tear secretion (Schirmer test) and tear stability (fluorescein break-up time (BUT) were determined in 121 healthy subjects and related to age and goblet cell count. None of the eyes thus investigated had any inflammatory or degenerative changes of the lids, conjunctiva or cornea. A low goblet cell count was found in subjects with a short BUT but a short BUT was not uniformly correlated with a certain goblet cell count. There was no clear relation between goblet cell count and BUT or basic tear secretion. Basic tear secretion and BUT decrease continuously after the age of 50 to about half the values obtained in younger individuals. The generally held view that values of below 10 mm (Schirmer test) and below 10 s (BUT) are pathologic cannot be maintained without caution.

[Dye-filling patterns in routine serial angiograms]

Rapid-sequence fluorescein angiograms of 127 healthy eyes with cilioretinal arteries were analyzed with regard to the time of dye entry into the central retinal artery, the cilioretinal artery and the choroid. In younger patients up to age 49) the cilioretinal artery filled simultaneously just as often as prior to the central retinal artery (42.9% and 41.4%, respectively); only rarely (15.7%) was a later filling noticed. In older persons (50 years of age and older) this filling pattern was reversed. The cilioretinal artery most frequently filled later than the central retinal artery (48.7%) and only rarely prior to it (15.8%). Similar results were obtained when comparing the filling time of the central retinal artery with the first choroidal fluorescein. With increasing age the circulation in the choroid and the cilioretinal arteries slows down in comparison to the central retinal artery, due to sclerotic vessel changes which have been shown to be much more pronounced in the choroidal vessels than in the retinal vessels. These findings are important for the understanding of age-related diseases of the optic nerve head, which derives almost all its blood supply from the choroidal circulation.

[Histological studies of goblet cell counts in human conjunctiva (author's transl)]

In 121 healthy subjects of all age groups the goblet cells were counted by means of conjunctival biopsies; none of these individuals showed any inflammatory or degenerative changes in their eye lids, conjunctivae or corneas. Three groups were distinguished: a small group with relatively few, a large group with an average number and a third small groups with a relatively large number of goblet cells. The number of goblet cells was usually between 26 and 40 to the square mm, but fluctuated to a great extent in all three groups. On determining age distribution, the average goblet cell counts were found to be astonishingly similar: they did not vary significantly in the different age groups. At most, one could say the goblet cell count is slightly lower from age 61 onward.

[Retinal circulation times as determined by fluorescein angiography (author's transl)]

Using a standardized technique of rapid fluorescein angiography applying a special diaphragm in the camera to reduce the patient stress by the frequent flashes and an automatic dye injection retinal circulation times of 173 healthy eyes were measured and statistically analysed. Circulation time was defined as the time interval between first visible arterial and venous fluorescence of corresponding vessels near the disc margin. The circulation time for the temporal vessels (1.1--1.2 s) was significantly faster than that of the nasal vessels (1.3 s) whereas there was no significant difference between the upper and lower main vessels. The very short circulation times are caused by short circuits near the disc. The difference between the shorter temporal and longer nasal times is caused by the macular circulation. It would therefore be more accurate to speak of peripapillary circulation times or of circulation times of the posterior pole of the fundus.

[Effects of dopamine and orciprenalin on human metabolism (author's transl)]

10 healthy probands were given on several subsequent days by intravenous infusion lasting 20' only orciprenalin and dopamine in therapeutic doses of 0.1 mg/kg bodyweight and 0.5 mg, respectively. In all cases application of orciprenalin resulted in a significant rise of glucose, insuline, lactate and free fatty acids. By contrast, no such changes were observed after infusion of dopamine. This suggests that a rise of free fatty acids in the serum may be important for the occurrence of cardiac arrythmia.